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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/4679

Title: Induction of phytoalexin accumulation in the cotyledons of selected legumes following treatments with biotic elicitors
Authors: Tengey, Theophilus Kwabla
Issue Date: 10-Jun-2012
Abstract: The accumulation of phytoalexins at the site of infection is one mechanism by which plants resist diseases. The general objective of this study was to investigate the potential of cowpea, soybean, groundnut and lima bean to synthesize and accumulate phytoalexins upon attack by fungi. Three genotypes each of cowpea, soybean and groundnut and a genotype of lima bean were used in the study. Lesions were produced in all fungus-inoculated cotyledons (elicited) 36 h after incubation whilst sterile distilled water-inoculated cotyledon surfaces which served as control did not produce lesions except cowpea which exhibited some lesions. Radial growth bioassay of concentrated cotyledon extracts obtained from fungus-inoculated cotyledons showed significantly (p ˂ 0.05) higher per cent inhibition of Curvularia lunata than extracts obtained from sterile distilled water-inoculated cotyledons. Thin layer chromatography bioassay also revealed that extracts obtained from fungus-inoculated cotyledons had more ultra violet (UV) absorbing compounds than extracts from sterile distilled water-inoculated cotyledons which among some genotypes did not show the presence of UV absorbing compounds. Localised fungitoxic activity were detected in the lanes of spotted fungus-inoculated concentrated extracts for a UV absorbing compound designated as L-I with Rf 0.07 in Lima bean and a non-UV absorbing compound in Azivivi, a groundnut genotype with Rf 0.92. The toxicity exhibited by these compounds indicates the defensive function of phytoalexins. The results of the experiment are discussed.
Description: A Thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the Degree of Master of Science in Agronomy (Plant Breeding), August-2012
URI: http://hdl.handle.net/123456789/4679
Appears in Collections:College of Agric and Natural Resources

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